The present invention relates to protection devices for preventing electric shocks by misuse of domestic appliances used in the home and more particularly to such devices used in electric toasters.
It is well recognized that if certain electric appliances are misused, electric shocks can result with the possibility of injuries. One typical situation of this type is where a person uses a metal (conductive) object such as a knife or fork to try to remove an object being toasted in a toaster that may have become jammed or wedged in the toaster while the toaster remains actively connected to a power source. While this danger is well recognized, unfortunately it still happens that injuries do occur by such misuse of toasters and other appliances.
Commonly in toasters the main carriage for supporting a bread slice (or the like) is capable of being moved downward to a toasting position against a main carriage spring force. The carriage is latched by some means in the toasting position for a desired toasting cycle whereupon, in normal cycle, the latching means releases the main carriage and the toasted product is carried upwardly under action of the main carriage spring. Normally, the movement towards the toasting position of the main carriage causes main electrical contacts (normally open) to be closed to supply power to the toasting elements. Release of the latching means and normal upward movement of the carriage as a result of the main carriage spring breaks these contacts to discontinue power to the toasting elements. The latching means might be some form of mechanical latching but such arrangements are not preferred in that they may remain latched if a general power failure occurs. Generally a more preferred form of latching is to use an electromagnet to retain the main carriage in the down or toasting position. In these arrangements, the carriage trips the main power contacts closed on its downward movement to supply power to the electromagnet and to the elements simultaneously with the power supply to the electromagnet and to the elements simultaneously with the power supply to the electromagnet being thereafter controlled by a suitable control means (e.g. a simple timer or a color control (browness device) to control the toasting cycle length. At the end of the cycle, power is removed from the electromagnet and the main carriage is released upwardly thereby also breaking the main power supply contacts. The foregoing of course describes "normal" operation of toasters. Unfortunately, occasions do arise where the main carriage might remain jammed or held (intentionally or otherwise) in its lowered position where the main power contacts remain closed resulting in the toasting elements staying in an electrically "live" condition even though a toasting cycle has been completed. Such jamming may occur as a result of a bread slice (or similar item) of irregular shape becoming wedged in a position inside the toasting compartment so that the main carriage will not move upward even though the electromagnetic force holding the carriage down has been removed. In other circumstances the carriage itself may become jammed in its lower position due to a mechanical fault or the like or a person might attempt to override the normal controls by simply physically holding the carriage down. Such circumstances can cause many different forms of accidents such as fires as a result of the toasting elements continuing to operate, or if an unthinking person attempts in the heat of the moment, to unblock a jam by inserting into the toasting compartment a conducting element such as a metal knife, fork or the like, that person immediately is at risk of injury. The same risk of course exists during normal operation of a toaster if a young child (or any other person without the requisite knowledge or mental capacity) inserts a conducting element into the toasting compartment while the toasting elements remain live.
The object therefore of the present invention is to provide a toaster control arrangement which will minimize the effect of electric shocks resulting from toaster misuse of the type discussed in the foregoing or will minimize the effect of other abnormal events with use of a toaster. A further preferred objective of the present invention is to provide a means for preventing continued power supply to the toasting elements upon completion of a toasting cycle regardless of the position of the main carriage.